LG GCR-8481B Service Manual

INTRODUCTION

GENERAL FEATURE

SPECIFICATIONS

1. MODEL: GCR-8481B

1) SUPPORTED SYSTEM

• IBM Compatible 486SX or Above (With PIO mode 4 recommended)

2) SUPPORTED OS

3) GENERAL PERFORMANCE

• Data Transfer Rate .........................................................................................Sustained Data Transfer Rate

20Times Speed (Inner side) : 3,000 kbytes/sec

48 Times Speed (max., Outer side) : 7,200 kbytes/sec

• Data Buffer Capacity.....................................................................................................................128 kbytes

• Average Access Time ........................................................................Random Access Time : 75 ms Typical

4) POWER REQUIREMENTS

• Voltage ......................................................................................................................................+5V DC +5%

+12V DC +5%

• Ripple ..................................................................................................................+5V : Less than 100mVp-p

+12V : Less than 100mVp-p

• Current .......................................................................................................................+5V : 0.9A (Maximum)

+12V : 1.5A (Maximum)

5) AUDIO PERFORMANCE

• Frequency Response.....................................................................................................20Hz~20KHz(+3dB)

• S/N Ratio (IHF-A+20 KHz LPF) .......................................................................80 dB (Typical at 1 KHz 0dB)

75 dB (Limit at 1 KHz 0dB)

• T.H.D. (IHF-A+20 KHz LPF)............................................................................0.05% (Typical at 1 KHz 0dB)

0.15% (Limit at 1 KHz 0dB)

• Channel Separation (IHF-A+20 KHz LPF).............................................................................80 dB (Typical)

70 dB (Limit)

• Output Level (1kHz 0dB) 47KΩ Load ....................................................................................0.7Vrms + 10%

• Headphone Level (1kHz 0dB) 33Ω Load...............................................................................0.7Vrms +

20%

• Enhanced IDE interface

• Internal 5.25 inch, halfheight CD-ROM Drive

• Fast 75ms Average Access Time

•

Max 7,200KB/sec Sustained Transfer rate (GCR-8481B)

• Max 7,800KB/sec Sustained Transfer rate (GCR-8521B)

• Photo-CD Multisession Disc Spec compliant

• Multimedia MPC-3 Spec compliant

• Power Tray Loading/Ejection Mechanism

• 3 Way Eject support (Software, O/C Button, Emergency Eject)

• Closed Enclosure

• Built-in ATAPI Interface Controller

• Software Volume Control

• 8 Times Digital Filter for CD Audio

• Built-in MODE-1 ECC/EDC

• MTBF 125,000h POH (at 10% Utilization)

• PIO Mode 4 & Multi DMA Mode 2 support

• Horizontal or Vertical Mounting

• Digital audio output connector

• Digital audio through ATAPI Interface

• Subcode (P-W) through ATAPI Interface

• Spin-down Mode for energy saving

• MS-DOS Version 3.1 or Higher

• Windows '95/'98/’2000/Me/XP

• Solaris Ver 2.4 or Higher

• Linux slackware Ver 2.3

• Windows NT 4.0 or later

• OS/2 Warp (Ver 3.0)

This service manual provides a variety of service information. It contains the mechanical structure of the CD-ROM Drive together with mechanical adjustments and the electronic circuits in schematic

form. This CD-ROM Drive was manufactured and assembled under our strict quality control standards and meets or exceeds industry specifications and standards.

2. MODEL: GCR-8521B

1) SUPPORTED SYSTEM

• IBM Compatible 486SX or Above (With PIO mode 4 recommended)

2) SUPPORTED OS

3) GENERAL PERFORMANCE

• Data Transfer Rate .........................................................................................Sustained Data Transfer Rate

21Times Speed (Inner side) : 3,150 kbytes/sec

52 Times Speed (max., Outer side) : 7,800 kbytes/sec

• Data Buffer Capacity.....................................................................................................................128 kbytes

• Access Time.......................................................................................Random Access Time : 75 ms Typical

4) POWER REQUIREMENTS

• Voltage ......................................................................................................................................+5V DC +5%

+12V DC +5%

• Ripple ..................................................................................................................+5V : Less than 100mVp-p

+12V : Less than 100mVp-p

• Current .......................................................................................................................+5V : 0.9A (Maximum)

+12V : 1.5A (Maximum)

5) AUDIO PERFORMANCE

• Frequency Response.....................................................................................................20Hz~20KHz(+3dB)

• S/N Ratio (IHF-A+20 KHz LPF) .......................................................................80 dB (Typical at 1 KHz 0dB)

75 dB (Limit at 1 KHz 0dB)

• T.H.D. (IHF-A+20 KHz LPF)............................................................................0.05% (Typical at 1 KHz 0dB)

0.15% (Limit at 1 KHz 0dB)

• Channel Separation (IHF-A+20 KHz LPF).............................................................................80 dB (Typical)

70 dB (Limit)

• Output Level (1kHz 0dB) 47KΩ Load ....................................................................................0.7Vrms + 10%

• Headphone Level (1kHz 0dB) 33Ω Load...............................................................................0.7Vrms + 20%

• MS-DOS Version 3.1 or Higher

• Windows '95/'98/’2000/Me/XP

• Solaris Ver 2.4 or Higher

• Linux slackware Ver 2.3

• Windows NT 4.0 or later

• OS/2 Warp (Ver 3.0)

3.3V Reg

2.5V Reg

+3.3V

+5V

+12V

+2.5V

GND

+5V

+12V

GND

SPINDLE

MOTOR

SLED

MOTOR

FOCUS

COIL

TRACKING

COIL

M63026FP

MOTOR DRIVE

Disc Motor unit

Optical Pick-up

CXA2581N RF Amp.

CXD3045R

DSP + Decoder + DRAM + System controller

33.86MHz

40MHz

I/F Cable

H O S T

AUDIO

Circuitry

R-ch

L-ch

Line-out

A B CD

BLOCK DIAGRAM

2. Trouble List (Circuit)

A. LED doesn’t light. B. Pick-Up doesn’t move to the inner-track. C. The Laser of Pick-Up doesn’t light. D. Pick-Up lens doesn’t move up and down. E. Disc doesn’t rotate. F. TOC isn’t read. (The LED turns on, but doesn’t flicker.) G. During Audio CD Play, LED flickers, but Speaker is silent.

TROUBLESHOOTING GUIDE

1. Initial Lead-in Operation

Reset or Power-On.

LED Flickers.

Pick-Up moves to the inner-Track.

Laser on the Pick-Up lights.

Focus Search (through moving up and down the lens of Pick-Up)

Focus Servo On (FOK :H, FEO(TP15) signal generation)

Rotate disc.

Tracking Servo On (TEO(TP14) Signal generation)

Spindle Servo On (SPO(TP25) Signal generation)

Read TOC Area (LED Flickers)

Search the Start of Data Area and then pause.

3. Troubleshooting Guide

A. LED doesn’t light.

Check Power Voltage (TP1:3.3V, TP20:2.5V, TP2:12V) Reference Voltage [TP3:DVC(1.35V) and GND.]

Does “H” output in IC501 pin ?

Check and replace R705, R706, Q701 and LED701.

Is the CLOCK Frequency of IC501 pin 33.86MHz?

Check the power input pattern.

Check IC501.

Check and replace X501; 33.86MHz, X502: 40MHz

Is the CLOCK Frequency of IC501 pin 33.86MHz?

Check and replace IC501.

YES

109

171

A-1

B. Pick-Up doesn’t move to the inner track.

Do the signals appear at IC501 pin , ? (Refer to Fig. B-1.)

Do the signals appear in PN301 pin?

Does “H” output at IC201 pin ?

Is the 1.35V at IC201 pin ?

Check the pattern from IC501 pin to IC201 pin

Check IC501.

Check the R190 and then replace IC102.

Check the PN301, and then replace the Sled Motor.

YES

Replace IC201.

106

CH1 PIN74 DA0

CH2 PIN73 DA1

CH1 TP4

CH2 TP5

CH3 TP6

CH4 TP7

Fig. B-1. DA0 and DA1 Signals

Fig. B-2. TP4, TP5, TP6 and TP7 Signals

Check the pattern from IC501 pin to R225 and then replace IC501.

Does “Low” or “High” output at IC102 pin ?

Is the voltage of IC102 pin (LD) 2V?

Check Pick-Up FFC, PN101.

Check Q101, C101, C102 and then replace IC102.

Check R118 and replace

IC501.

YES

Does the focus search signal appear at FAO (TP9)? (Refer to Fig. D-1.)

Is the 1.35V at IC201 pin ?

Check the R190 and then replace IC102.

YES

Replace IC201.

Does the focus search signal appear between F+ (TP10) and F- (TP11)? (Refer to Fig. D-2.)

C. The Laser of Pick-Up doesn’t light.

D. The Pick-UP lens doesn’t move up and down.

D-1

Check the pattern from pin , of IC201 to pin , of PN101.

Check the PN101, Pick-Up FFC.

Replace the Pick-Up.

Replace PN101 or Pick-Up FFC.

CH1 TP9 (FAO)

CH1 TP10(F+) TP11(F-)

Fig. D-1. FAO Signal

Fig. D-2. Focus Search Signal

D-1

+ 16 hidden pages

LG GCR-8481B Service Manual

Specifications and Main Features

Frequently Asked Questions

User Manual